The present invention relates generally to electrochemical cell and fuel cell technology and, more particularly, to fuel cell modules including microfiber fuel cells or microtubular fuel cells, also known as microcells.
A fuel cell is a type of electrochemical energy device similar to a battery. A fuel cell includes a cathode and an anode separated by a membrane. A fuel, such as hydrogen, is supplied to the anode side of the fuel cell, while an oxidant, such as oxygen, is supplied to the cathode side of the fuel cell. The hydrogen splits into positive hydrogen ions and negatively-charged electrons. The membrane separator allows the positively-charged ions to pass through to the cathode side of the fuel cell. The negatively-charged electrons, however, must travel through an electric circuit to the cathode, thus creating an electrical current. At the cathode side of the fuel cell, the electrons and positively-charged hydrogen ions combine with oxygen to form water.
Microfiber fuel cells or microtubular fuel cells, also called microcells, represent one promising fuel cell technology. A microcell is a fiber-like fuel cell wherein the inner and outer current collectors, membrane separator and catalyst layers are extruded as a single fiber. The fibers may range in size from a few hundred to several thousand microns. One advantage of the fuel cell topology is that is achieves the highest possible Membrane Electrode Assembly (MEA) surface area to volume ratio, resulting in compact fuel cells. Another advantage is its scalability. The microcells can be assembled together in bundles to form units called unicells. The unicells can be further bundled to form larger units called modules.